Changes in the functional and proliferative capacities of cells of the vascular system contribute significantly to age related functional decline in whole animals. During the last few years considerable progress has been made in studying the growth, function and characterization of normal vascular cells in culture. Since the in vivo function and characteristics of these cells are well known, they offer an excellent opportunity to study the relationship between in vivo and in vitro cellular aging. Although these cells provide an excellent opportunity for studies at the cellular level, relatively few such studies are currently being conducted. One of the major purposes of this symposium is to stimulate a wide range of studies on the cellular aging of the vascular system. This symposium will serve two main functions: 1) To stimulate interest in the field of cellular aging, especially on the part of those investigators already studying vascular tissue, 2) to acquaint those investigators already in the field of cellular aging with the possibilities for the use of cells from the vascular tissue in their studies. This will be accomplished through a series of 45-50 minute lectures, laboratory demonstrations, presentation of short (approximately 10 min) papers and poster sessions.